sporulation

formation of exospores and endospores

1. MICROBIOLOGY SPORULATION By keerthana.c

2. What are spores? It is a unicellular structure. Spores form a life cycle in many plants, algae, bacteria, fungi and protozoa. Spores are formed during unfavorable conditions. They can survive without nutrients. it forms highly resistant structure.

3. Types of spores There are two types of spore 1) endospores. 2) exospores. Endospores- are formed within the vegetative cell . (inside the cell). Exospores- are formed in either one of the ends of the vegetative cell. (on the surface of the cell).

4. Structure of spore

5. structure The outer and inner coat made up of protein and they provides chemical and enzymatic resistance to the spores. Cortex region lies between the region of outer and inner coat and it is made up of peptidoglycon. Cortex helps in dehydration process during sporulation process and thus providing high temperature resistance .

6. Germ cell wall protects from potentially damaging chemicals and it protects the central core. The central core portion consists of DNA, small amounts of RNA, ribosomes , enzymes and nearly 40% of dipiclonic acid. (DPA) This DPA helps in preventing the damage against DNA by chemicals present in the environment.

7. sporulation The process of production of spores is called sporulation or sporogenesis. The one vegetative cell forms a single spore , which, after germination, develops into a new cell. It takes 8hrs-19 hrs to compelete .

8. Endospores formation

9. Exospores formation

10. Exospores development In exospores formation spores developed outside the body. They developed attached with a outer surface of the cell wall. During the unfavorable conditions Primarily, the mother cell and the daughter cells are divided by means of the septum and later it forms a bud like structure at the outer covering.

11. The cytoplasmic division results in the bud and it is covered by a double layered membrane. Later it is followed by outer and inner coat development and thus resulting exospores During favorable conditions the bud get detached from the body and it is followed by germination.

12. germination Sporulation is followed by germination. An endospores and exospores returns to its vegetative state by a process called germination. Germination is triggered by physical or chemical damage to the endospores coat.

13. When the environmental conditions become favor of the bacteria, the spores are reactivated and thus giving rise to a new bacterial cell. This is not a process of reproduction Vegetative cell produces a single spore which in turn forms a new bacterial cell.

14. Sigma factor A  sigma factor  ( σ factor ) is a protein needed only for initiation of RNA synthesis .  It is a bacterial transcription initiation factor that enables specific binding of RNA polymerase to gene promoters.

15. The specific sigma factor used to initiate transcription of a given gene will vary, depending on the gene and on the environmental signals needed to initiate transcription of that gene. Depending upon the environment it also initiates sporulation process.

16. Thank you